919802-97-4Relevant articles and documents
Inverse electron demand diels-alder reactions of 1,2,3-triazines: Pronounced substituent effects on reactivity and cycloaddition scope
Anderson, Erin D.,Boger, Dale L.
supporting information; experimental part, p. 12285 - 12292 (2011/09/16)
A systematic study of the inverse electron demand Diels-Alder reactions of 1,2,3-triazines is disclosed, including an examination of the impact of a C5 substituent. Such substituents were found to exhibit a remarkable impact on the cycloaddition reactivity of the 1,2,3-triazine without altering, and perhaps even enhancing, the intrinsic cycloaddition regioselectivity. The study revealed not only that the reactivity may be predictably modulated by a C5 substituent (R = CO2Me > Ph > H) but also that the impact is of a magnitude to convert 1,2,3-triazine (1) and its modest cycloaddition scope into a heterocyclic azadiene system with a reaction scope that portends extensive synthetic utility, expanding the range of participating dienophiles. Significantly, the studies define a now powerful additional heterocyclic azadiene, complementary to the isomeric 1,2,4-triazines and 1,3,5-triazines, capable of dependable participation in inverse electron demand Diels-Alder reactions, extending the number of complementary heterocyclic ring systems accessible with implementation of the methodology.
Synthesis of 4-arylpyrazoles via PdCl2(dppf)-catalyzed cross coupling reaction with Grignard reagents
Ichikawa, Hayato,Ohno, Yuuki,Usami, Yoshihide,Arimoto, Masao
, p. 2247 - 2252 (2007/10/03)
4-Aryl-l-tritylpyrazoles were prepared from the cross coupling reaction of aryl Grignard reagents with 4-bromo-1-tritylpyrazoles in the presence of 0.2 mol% PdCl2(dppf) as catalyst. To deprotect the trityl group, 4-phenyl-l-tritylpyrazole was r
